Acetylcholine is a neurotransmitter that induces signal transduction in the central nervous system and the neuromuscular connections (the parasympathetic nerve and motor nerve). In the central nervous system, nuclei of origin of the acetylcholine neuron are in the brain stem and forebrain, and those acetylcholine neurons project to cerebral cortex, hippocampus, and limbic area. In addition, some interneurons in some brain areas such as striatum utilize acetylcholine as a neurotransmitter. Acetylcholine receptor is classified into a ligand dependent-ion channel (cholinergic nicotinic receptor) and a G-protein-coupled receptor (cholinergic muscarinic receptor). The cholinergic muscarinic receptor is one kind of receptor for excitatory neurotransmitter, acetylcholine, and was named based on the selective activation of the receptor by muscarine. The muscarinic receptor is further classified into subtypes of M1 to M5. The M1 receptor is known to be mainly distributed in the brain, and deeply involved particularly in learning, memory, sleep, neuropathic pain, and the like. The importance of cholinergic muscarinic M1 receptor in brain physiology is well known, and a compound which enhances M1 receptor function is expected to be useful as an agent for the prophylaxis or treatment of mental diseases, neurodegenerative diseases, memory disorders, pain, sleep disorders, Parkinson's disease dementia, dementia with Lewy bodies and the like (non-patent document 1).
WO 02/081447 A1 (Patent Document 1) discloses the following compound as a compound having a tumor necrosis factor-α (TNF-α) or a cAMP phosphodiesterase IV (PDE4) inhibitory activity and useful for the prophylaxis or treatment of inflammation and autoimmune disease.
wherein each symbol is as defined in the document.
WO 02/081446 A1 (Patent Document 2) discloses the following compound as a compound having a tumor necrosis factor -α (TNF-α) or a cAMP phosphodiesterase IV (PDE4) inhibitory activity and useful for the prophylaxis or treatment of inflammation and autoimmune disease.
wherein each symbol is as defined in the document.
WO 2006/020879 A1 (Patent Document 3) discloses the following compound as a glutamic acid receptor potentiator useful for the prophylaxis or treatment of psychoneurotic disorder associated with glutamate dysfunction.
wherein each symbol is as defined in the document.
WO 2013/063549 A1 (Patent Document 4) discloses the following compound as a compound useful for the prophylaxis or treatment of psychoneurotic disorder associated with muscarinic acetylcholine receptor dysfunction.
wherein each symbol is as defined in the document.
Bioorganic & Medicinal Chemistry Letters, 20 (2010) 1792-1975 (Non-Patent Document 2) discloses the following compound as an M1 receptor positive allosteric modulator.

Gordon, C. P., Byrne, N., McCluskey, A. Green Chem., 2010, 12, 1000-1006. (Non-Patent Document 3) discloses the following compound similar to the compound of the present invention.

WO 2010/096338 A1 (Patent Document 5) discloses the following compound as an M1 receptor positive allosteric modulator useful for the prophylaxis or treatment of a Alzheimer's disease, schizophrenia, pain or sleep disorder.
wherein each symbol is as defined in the document.
WO 95/030647 A1 (Patent Document 6) discloses the following compound similar to the compound of the present invention.
wherein each symbol is as defined in the document.
WO 2007/139464 A1 (Patent Document 7) discloses the following compound as a CB1 receptor ligand useful for the prophylaxis or treatment of pain, cancer, multiple sclerosis, Parkinson's disease, Huntington's disease, Alzheimer's disease, anxiety disorder, gastrointestinal disorder and cardiovascular disorder.
wherein each symbol is as defined in the document.
US 2008/0108659 A1 (Patent Document 8) discloses the following compound as a compound having poly(ADP ribose) polymerase (PARP) activity and useful for the prophylaxis or treatment of cancer, central nervous system disease, inflammation disease and the like.
wherein each symbol is as defined in the document.
WO 2011/006794 A1 (Patent Document 9) discloses the following compound as a compound selectively inhibiting an activity of poly (ADP-ribose) polymerase PARP-1 with respect to poly (ADP-ribose) polymerase PARP-2 and useful for the prophylaxis or treatment of cancer, cardiovascular disorder, central nervous system disorder and the like.
wherein each symbol is as defined in the document.
WO 2012/003147 A1 (Patent Document 10) discloses the following compound as a compound having an M1PAM activity and useful for the prophylaxis or treatment of Alzheimer's disease, schizophrenia, pain, sleep disorder and the like.
wherein each symbol is as defined in the document.
WO 2012/158475 A1 (Patent Document 11) discloses the following compound as a compound having an M1PAM activity and useful for the prophylaxis or treatment of Alzheimer's disease and other diseases.
wherein each symbol is as defined in the document.
JP-B-S44-16647 (Patent Document 12) discloses the following compound similar to the compound of the present invention.
